Popular Junction Box Sizes

RonHebbard

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Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Hello all,

Depending on the size of terminations and cabling how do you prefer your junction box size? What is the most common size for sound application in large venues with over 25 speakers and 50 connections?

What are best practices when using a junction box?

Any links to resources are very appreciated.

Thanks!
@Cezary Oniszczuk Hello Cezary; Your single question leads immediately to many more.
Are your various cables routed via conduit?
Can I assume you're segregating various systems and sub-systems into individual boxes and conduits rather than enclosing all systems within any one box?
Surely you're segregating balanced microphone level signals from low impedance and / or 70 volt speaker level signals.
I'm interpreting your query to junction boxes and terminations totally within the box as distinct from boxes with mateable / de-mateable connectors neatly arranged and identified on their covers for regular use in interfacing with portable equipment on a regular basis.
Narrow your question and I'm confident many will reply with their preferences.
Toodleoo!
Ron Hebbard.
 

MNicolai

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Mar 30, 2008
Location
Sarasota, FL
Really depends on the types of of connectors, quantity, if it's flush or surface mount, how deep the wall is, and how many cables need to be cable managed behind the panel

The minimum size I use is 4" square with a 1- or 2-gang ring. Minimum depth 3-1/2". Except for extraneous XLR connectors I don't allow typical masonry-type gang boxes.

Most back boxes I spec are 4" deep. Some are 6" if I need to fit a transmitter or a CAT6/CAT6A connector that doesn't have a 90° termination option to it or I have coax cable in that box. I'll go as deep as 8" sometimes if I need something with a MASS connector on it so there's room enough for strain relief and service loop behind the panel.

I use a lot of 6" square boxes with 1-, 2-, or 3-gang rings, which gives room for cable bend radius and service loop.

When it comes to speaker connections, I spec the NL4 panel mount connectors with flat tabs so all connections are crimped rather than soldered or screwed. This doesn't usually affect back box depth but it makes the terminations easier and less prone to error. Also makes it easy to fix when the new guy flips polarity all over the place.

If you try to use something non-standard like a 14" x 14" back box, your electricians will beat you up and tell you they don't make a box like that. They do, actually, but it's special order and not widely available.

Also have to account for spacing between connectors both for rear-access terminating, and for front-access visibility of labels and room for getting your fingers in to press the latches and twist.

Along the top/bottom/sides, best to to have the electricians pipe into the rear of the box rather than along the front. If they pipe in near the front or the box is too shallow, your connectors will crunch down on your cables where they enter the box via conduit.
 

RonHebbard

Well-Known Member
Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Really depends on the types of of connectors, quantity, if it's flush or surface mount, how deep the wall is, and how many cables need to be cable managed behind the panel

The minimum size I use is 4" square with a 1- or 2-gang ring. Minimum depth 3-1/2". Except for extraneous XLR connectors I don't allow typical masonry-type gang boxes.

Most back boxes I spec are 4" deep. Some are 6" if I need to fit a transmitter or a CAT6/CAT6A connector that doesn't have a 90° termination option to it or I have coax cable in that box. I'll go as deep as 8" sometimes if I need something with a MASS connector on it so there's room enough for strain relief and service loop behind the panel.

I use a lot of 6" square boxes with 1-, 2-, or 3-gang rings, which gives room for cable bend radius and service loop.

When it comes to speaker connections, I spec the NL4 panel mount connectors with flat tabs so all connections are crimped rather than soldered or screwed. This doesn't usually affect back box depth but it makes the terminations easier and less prone to error. Also makes it easy to fix when the new guy flips polarity all over the place.

If you try to use something non-standard like a 14" x 14" back box, your electricians will beat you up and tell you they don't make a box like that. They do, actually, but it's special order and not widely available.

Also have to account for spacing between connectors both for rear-access terminating, and for front-access visibility of labels and room for getting your fingers in to press the latches and twist.

Along the top/bottom/sides, best to to have the electricians pipe into the rear of the box rather than along the front. If they pipe in near the front or the box is too shallow, your connectors will crunch down on your cables where they enter the box via conduit.
@MNicolai and @Cezary Oniszczuk I completely agree and remind you both to keep fiber / fibre in mind along with its prescribed handling / minimum bending radiuses / radii including lengths and space required to remove any face plates for internal access.
Toodleoo!
Ron Hebbard.
 

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